The present invention pertains generally to computers, and more particularly to a system for adding functionality to a computer system in a modular fashion.
Referring now to FIG. 1, there is shown a prior art computer system 10 with a PCI bus 18 and PCI card 22. As used herein, the term xe2x80x9cPCIxe2x80x9d shall refer to the standard specified in the PCI Local Bus Specification, Revision 2.2, 1998, and all past or future superceded or superceding standards or other standards equivalent thereto or backward or forward compatible in whole or in part therewith. Further, terms such as xe2x80x9cPCI busxe2x80x9d, xe2x80x9cPCI cardxe2x80x9d and xe2x80x9cPCI slotxe2x80x9d shall mean cards, busses or slots compatible or compliant with a PCI standard. A main board 12 includes a main board chip set 14 mounted thereon. Chip set 14 includes a PCI controller 16, which is connected to a PCI slot 20 over PCI bus 18. PCI card 22 includes a PCI card controller 24, which in turn includes a link controller circuit 26, which connects to link interface 30 through proxy link 28. Link interface 30 interfaces to CODEC or network PHY circuit 32, which in turn provides an I/O connection 34. A CPU or processor mounted on the main board communicates with and controls chip set 14.
The above described PCI bus 18 is used to attach various I/O functions to the computer main board 12 in a modular fashion. Typically, computer systems are provided with one or more PCI card slots 20 to provide equipment manufacturers and end users the ability to add custom features to the system. The present invention, as described below, provides an improvement to the above described prior art system and its PCI bus.
The present invention provides method and apparatus for providing PCI board functionality wherein, in one example embodiment, the control logic for a PCI card is mounted on the main board of a computer system having a PCI bus and PCI slots to receive PCI cards. The PCI card functionality is controlled from the PCI control logic on the main board using a proxy link to the PCI card functionality, wherein the proxy link is routed over the PCI bus. Further, such embodiment provides that a standard PCI card, with the control logic mounted thereon, may also function normally when inserted in one of the PCI slots in the system. This and many other embodiments are described in more detail below.